The present embodiments relate to a magnetic resonance coil apparatus.
A magnetic resonance examination may take up to an hour or longer for a patient to be examined. For the duration of a magnetic resonance examination, the patient may lie as still as possible on a patient support apparatus to prevent falsification of the measurement and/or artifacts in the magnetic resonance images.
A distinction is made between two types of patient movement during the magnetic resonance examination: rigid patient movement and non-rigid patient movement. In the case of rigid patient movements, the object to be measured only moves in its entirety. Movement within the object does not take place (e.g., the head of the patient). In the case of non-rigid patient movements, however, the object may also change form and/or move (e.g., the bowel of the patient or a patient's eye movement).
Different approaches have already been adopted for magnetic resonance imaging in order to make the magnetic resonance examination less sensitive with respect to patient movement. A radial acquisition (BLADE), for example, is used for this purpose. Alternatively or additionally, magnetic resonance-based monitoring, with which patient movement is determined by short intermediate scans or navigator scans for locating the patient, may also be used. External marker elements positioned on the patient may also be provided. With the aid of external marker elements, patient movement may be observed from outside by conventional, external camera elements (e.g., using a conventional video camera). The patient movement detected during magnetic resonance measurement is used so that the patient movement results in corrections during postprocessing of the detected magnetic resonance signals. The corrections cancel out patient movements in the measurement data. Information about patient movement (e.g., where the patient movement is significant) also results in the repetition of at least one subregion of magnetic resonance measurement.
The detection of patient movement by external marker elements also uses additional (e.g., externally disposed) optical elements (e.g., a conventional video camera). However, only rigid patient movement may be detected by the external marker elements and the conventional video camera. If local magnetic resonance coils, however, are used for the magnetic resonance examination, movement detection by external marker elements and the conventional, externally disposed video camera may be problematic. For example, an optical field of view of a conventional, externally disposed video camera may be covered by a housing of the local magnetic resonance coil. The arrangement and/or use of conventional, externally disposed video cameras for capturing patient movement data may also impede the magnetic resonance examination, in that the video cameras may restrict the receiving region for the patient because of the size and field of view of the video cameras. Also, because of spatial extension, conventional video cameras may be disposed outside the patient examination region of the magnetic resonance apparatus and/or the local magnetic resonance coil, again impeding the detection of patient movement.